/*
 * Copyright (c) 2002, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 *
 */

package javax.swing.plaf.synth;

import javax.swing.*;
import javax.swing.text.JTextComponent;
import javax.swing.border.*;
import javax.swing.plaf.*;
import javax.swing.plaf.basic.*;

import java.beans.PropertyChangeListener;
import java.beans.PropertyChangeEvent;

import java.awt.*;
import java.awt.event.ContainerListener;
import java.awt.event.ContainerEvent;
import java.awt.event.FocusListener;
import java.awt.event.FocusEvent;

/**
 * Provides the Synth L&amp;F UI delegate for
 * {@link javax.swing.JScrollPane}.
 *
 * @author Scott Violet
 * @since 1.7
 */
public class SynthScrollPaneUI extends BasicScrollPaneUI
    implements PropertyChangeListener, SynthUI {

  private SynthStyle style;
  private boolean viewportViewHasFocus = false;
  private ViewportViewFocusHandler viewportViewFocusHandler;

  /**
   * Creates a new UI object for the given component.
   *
   * @param x component to create UI object for
   * @return the UI object
   */
  public static ComponentUI createUI(JComponent x) {
    return new SynthScrollPaneUI();
  }

  /**
   * Notifies this UI delegate to repaint the specified component.
   * This method paints the component background, then calls
   * the {@link #paint(SynthContext, Graphics)} method.
   *
   * <p>In general, this method does not need to be overridden by subclasses.
   * All Look and Feel rendering code should reside in the {@code paint} method.
   *
   * @param g the {@code Graphics} object used for painting
   * @param c the component being painted
   * @see #paint(SynthContext, Graphics)
   */
  @Override
  public void update(Graphics g, JComponent c) {
    SynthContext context = getContext(c);

    SynthLookAndFeel.update(context, g);
    context.getPainter().paintScrollPaneBackground(context,
        g, 0, 0, c.getWidth(), c.getHeight());
    paint(context, g);
    context.dispose();
  }

  /**
   * Paints the specified component according to the Look and Feel.
   * <p>This method is not used by Synth Look and Feel.
   * Painting is handled by the {@link #paint(SynthContext, Graphics)} method.
   *
   * @param g the {@code Graphics} object used for painting
   * @param c the component being painted
   * @see #paint(SynthContext, Graphics)
   */
  @Override
  public void paint(Graphics g, JComponent c) {
    SynthContext context = getContext(c);

    paint(context, g);
    context.dispose();
  }

  /**
   * Paints the specified component.
   *
   * @param context context for the component being painted
   * @param g the {@code Graphics} object used for painting
   * @see #update(Graphics, JComponent)
   */
  protected void paint(SynthContext context, Graphics g) {
    Border vpBorder = scrollpane.getViewportBorder();
    if (vpBorder != null) {
      Rectangle r = scrollpane.getViewportBorderBounds();
      vpBorder.paintBorder(scrollpane, g, r.x, r.y, r.width, r.height);
    }
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public void paintBorder(SynthContext context, Graphics g, int x,
      int y, int w, int h) {
    context.getPainter().paintScrollPaneBorder(context, g, x, y, w, h);
  }

  /**
   * {@inheritDoc}
   */
  @Override
  protected void installDefaults(JScrollPane scrollpane) {
    updateStyle(scrollpane);
  }

  private void updateStyle(JScrollPane c) {
    SynthContext context = getContext(c, ENABLED);
    SynthStyle oldStyle = style;

    style = SynthLookAndFeel.updateStyle(context, this);
    if (style != oldStyle) {
      Border vpBorder = scrollpane.getViewportBorder();
      if ((vpBorder == null) || (vpBorder instanceof UIResource)) {
        scrollpane.setViewportBorder(new ViewportBorder(context));
      }
      if (oldStyle != null) {
        uninstallKeyboardActions(c);
        installKeyboardActions(c);
      }
    }
    context.dispose();
  }

  /**
   * {@inheritDoc}
   */
  @Override
  protected void installListeners(JScrollPane c) {
    super.installListeners(c);
    c.addPropertyChangeListener(this);
    if (UIManager.getBoolean("ScrollPane.useChildTextComponentFocus")) {
      viewportViewFocusHandler = new ViewportViewFocusHandler();
      c.getViewport().addContainerListener(viewportViewFocusHandler);
      Component view = c.getViewport().getView();
      if (view instanceof JTextComponent) {
        view.addFocusListener(viewportViewFocusHandler);
      }
    }
  }

  /**
   * {@inheritDoc}
   */
  @Override
  protected void uninstallDefaults(JScrollPane c) {
    SynthContext context = getContext(c, ENABLED);

    style.uninstallDefaults(context);
    context.dispose();

    if (scrollpane.getViewportBorder() instanceof UIResource) {
      scrollpane.setViewportBorder(null);
    }
  }

  /**
   * {@inheritDoc}
   */
  @Override
  protected void uninstallListeners(JComponent c) {
    super.uninstallListeners(c);
    c.removePropertyChangeListener(this);
    if (viewportViewFocusHandler != null) {
      JViewport viewport = ((JScrollPane) c).getViewport();
      viewport.removeContainerListener(viewportViewFocusHandler);
      if (viewport.getView() != null) {
        viewport.getView().removeFocusListener(viewportViewFocusHandler);
      }
      viewportViewFocusHandler = null;
    }
  }

  /**
   * {@inheritDoc}
   */
  @Override
  public SynthContext getContext(JComponent c) {
    return getContext(c, getComponentState(c));
  }

  private SynthContext getContext(JComponent c, int state) {
    return SynthContext.getContext(c, style, state);
  }

  private int getComponentState(JComponent c) {
    int baseState = SynthLookAndFeel.getComponentState(c);
    if (viewportViewFocusHandler != null && viewportViewHasFocus) {
      baseState = baseState | FOCUSED;
    }
    return baseState;
  }

  public void propertyChange(PropertyChangeEvent e) {
    if (SynthLookAndFeel.shouldUpdateStyle(e)) {
      updateStyle(scrollpane);
    }
  }


  private class ViewportBorder extends AbstractBorder implements UIResource {

    private Insets insets;

    ViewportBorder(SynthContext context) {
      this.insets = (Insets) context.getStyle().get(context,
          "ScrollPane.viewportBorderInsets");
      if (this.insets == null) {
        this.insets = SynthLookAndFeel.EMPTY_UIRESOURCE_INSETS;
      }
    }

    @Override
    public void paintBorder(Component c, Graphics g, int x, int y,
        int width, int height) {
      JComponent jc = (JComponent) c;
      SynthContext context = getContext(jc);
      SynthStyle style = context.getStyle();
      if (style == null) {
        assert false : "SynthBorder is being used outside after the " +
            " UI has been uninstalled";
        return;
      }
      context.getPainter().paintViewportBorder(context, g, x, y, width,
          height);
      context.dispose();
    }

    @Override
    public Insets getBorderInsets(Component c, Insets insets) {
      if (insets == null) {
        return new Insets(this.insets.top, this.insets.left,
            this.insets.bottom, this.insets.right);
      }
      insets.top = this.insets.top;
      insets.bottom = this.insets.bottom;
      insets.left = this.insets.left;
      insets.right = this.insets.left;
      return insets;
    }

    @Override
    public boolean isBorderOpaque() {
      return false;
    }
  }

  /**
   * Handle keeping track of the viewport's view's focus
   */
  private class ViewportViewFocusHandler implements ContainerListener,
      FocusListener {

    public void componentAdded(ContainerEvent e) {
      if (e.getChild() instanceof JTextComponent) {
        e.getChild().addFocusListener(this);
        viewportViewHasFocus = e.getChild().isFocusOwner();
        scrollpane.repaint();
      }
    }

    public void componentRemoved(ContainerEvent e) {
      if (e.getChild() instanceof JTextComponent) {
        e.getChild().removeFocusListener(this);
      }
    }

    public void focusGained(FocusEvent e) {
      viewportViewHasFocus = true;
      scrollpane.repaint();
    }

    public void focusLost(FocusEvent e) {
      viewportViewHasFocus = false;
      scrollpane.repaint();
    }
  }
}
